The menu layout is different on Categories and other pages

The menu layout is different on Categories page and home/other page. How can I fix it?
i.e. the menu is on two lines on categories page and the line color below the menu item is orange, while the menu is on single line on home page and the line color is blue. How can I make the same layout (either orange one or the blue one) but yes, on single line 🙂